SECONDARY  INFECTION  IN  PULMONARY 
TUBERCULOSIS.  THE  RECOVERY  OF 
THE  STREPTOCOCCUS  AND  PNEU- 
MOCOCCUS  FROM  THE  BLOOD 


ROSWELL  T.  PETTfr 


Reprinted  from 

The  Journal  of  Infectious  Diseases,  Vol.  IX,  No.  3,  November  1911,  pp.  237-250 


CHICAGO 


'  "  "  ^ 


SECONDARY  INFECTION  IN  PULMONARY  TUBERCU- 
LOSIS.   THE  RECOVERY  OF  THE  STREPTOCOCCUS 
AND  PNEUMOCOCCUS  FROM  THE  BLOOD. *t 

RoswellT.  Petti T, 

{From  the  Ottawa  Tent  Colony,  Ottawa,  III.) 

The  degree  of  importance  of  secondary  infections  in  pulmonary 
tuberculosis  is  a  much  disputed  question.  A  certain  group  of 
observers  consider  the  tubercle  bacillus  as  responsible  for  prac- 
tically all  the  pathological  conditions  in  tuberculosis  of  the  lung, 
while  others  believe  that  the  secondary  invaders,  more  often 
streptococci,  pneumococci,  and  staphylococci,  play  a  very  large 
role  in  the  production  of  the  changes.  Between  these  two  extremes 
stand  those  who  assign  a  certain  import  to  both  the  primary  and 
the  secondary  invaders:  some  holding  the  opinion  that  the  major 
role  is  played  by  the  tubercle  bacillus,  others  that  the  tubercle 
bacillus  is  of  lesser  importance  and  that  the  major  role  is  played 
by  the  secondary  invaders. 

There  is  a  large  amount  of  evidence  advanced  in  support  of 
each  of  these  views.  This  evidence,  however,  is  for  the  most  part 
incomplete  and  contradictory.  The  complexity  of  the  problem  is 
such  that  many  of  the  methods  which  have  been  employed  are  of 
little  value  in  furnishing  reliable  data,  and  in  reviewing  the  litera- 
ture one  is  impressed  with  the  great  variety  of  conclusions  drawn, 
even  by  those  using  the  same  methods  of  investigation. 

Seven  methods  of  attack  have  been  variously  employed  in  the 
study  of  secondary  infection  in  pulmonary  tuberculosis,  namely: 
(i)  the  direct  observation  of  clinical  phenomena,  (2)  anim.al 
experimentation,  (3)  bacteriological  and  anatomical  examination 
of  the  lung  after  death,  (4)  bacteriological  study  of  the  sputum, 
(5)  study  of  the  opsonic  index,  (6)  study  of  the  leukocytes,  and 
(7)  blood  cultures. 

*  Received  for  publication  July  i8,  igii. 

t  Financial  support  of  this  work  was  afforded  by  the  Max  Pam  Research  Fund. 

237 


238 


RoswELL  T.  Pettit 


The  study  of  the  clinical  phenomena  has  led  to  direct  contradictions.  Baumler,' 
for  instance,  believes  the  frequent  occurrence  of  bronchopneumonia  after  hemor- 
rhage to  be  due  to  secondary  infection,  while  Sorgo^  contends  that  the  tubercle  bacillus 
itself  is  capable  of  producing  the  bronchitis  or  pneumonia. 

Czaplewski,  Ziegler,  Maragliano,  Weichselbaum,  and  Strumpel  (all  cited  by 
Cornet^)  on  the  basis  of  clinical  studies,  believe  that  secondary  organisms  are  intimately 
concerned  in  the  pathology  of  chronic  pulmonary  phthisis  and,  on  the  same  basis. 
Cornet  and  Petruschky^  are  convinced  that  the  steep  temperature  curve  frequently 
seen  in  chronic  pulmonary  tuberculosis  is  due  to  a  mixed  infection.  On  the  other 
hand.  Picks  points  out  that  this  type  of  fever  has  been  observed  in  cases  showing  only 
tubercle  bacilli  in  the  sputum  and  no  secondary  organisms  in  the  tissues  after  death. 

Rapid  emaciation,  excessive  weakness,  cough,  profuse  expectoration,  chills,  and 
sweats  are  all  attributed  to  the  presence  of  secondary  pyogenic  organisms;  on  the  other 
hand,  individuals  having  many  secondary  organisms  in  the  sputum  and  pronounced 
cavities  may  not  show  fever,  sweats,  or  emaciation  (Sorgo) . 

Likewise  the  evidence  based  upon  animal  experiment  is  in  a  large  measure  con- 
tradictory. Prudden,^  for  instance,  found  that  the  inoculation  of  tubercle  bacilli 
into  rabbits  produced  tuberculosis,  but  seldom  caused  cavities;  the  intratracheal 
injection  of  streptococci  into  tuberculous  animals,  however,  caused  marked  cavity 
formation.  Marmorek,7  on  the  other  hand,  was  able  to  produce  cavities  by  injecting 
pure  cultures  of  tubercle  bacilli  together  with  large  quantities  of  their  toxins. 

The  evidence  contributed  by  bacteriological  and  anatomical  examination  of  the 
lung  after  death  is  to  a  large  degree  unreliable — postmortem,  agonal,  and  terminal 
invasions  being  complicating  factors  of  marked  frequency  and  extent.  However, 
secondary  organisms  have  been  described  in  the  walls  of  cavities  where  during  life 
they  kept  pace  with  the  tubercle  bacillus,  or  even  preceded  it  in  the  invasion  of  healthy 
tissue  (Cornet).  Kossel  and  Cornet  have  both  found  secondary  organisms  in  tubercles 
in  the  liver  and  spleen  widely  separated  from  the  original  seat  of  infection. 

Sputum  examination  has  been  employed  extensively  in  the  study  of  secondary 
infections  in  pulmonary  tuberculosis,  but  this  method  again  must  be  recognized  as 
having  sharp  limitations.  It  is  a  well-known  fact  that  all  organisms  present  in  mixed 
infections  in  tuberculosis  may  also  be  found  in  the  healthy  mouth,  pharynx,  and 
trachea.  Whether  these  organisms  may  be  present  normally  in  the  alveoli  of  the  lung 
is  an  open  question.*  Little  more  weight  can  be  given  to  the  results  obtained  by 
examination  of  washed  tuberculous  sputum,  although  the  results  of  Kitasato,^  Pe- 
truschky,^°  Spengler,"  Schabad,^^  and  Cornet  agree  in  designating  the  streptococcus 
as  the  secondary  organism  most  constantly  recovered  in  such  examinations.  Sorgo 
maintains  that  the  amount  of  washing  used  by  these  observers  was  not  sufhcient,  and 
according  to  his  extremely  stringent  rules  mixed  infection  is  much  more  rare  than  the 
above  observers  are  led  to  believe. 

'  Deut.  med.  Wchnschr.,  1893,  19,  p.  i.  ^  Ztschr.f.  klin.  Med.,  1907,  51,  p.  250. 

3  "Tuberculosis  and  Acute  General  Miliary  Tuberculosis"  in  Nothnagel's  Practice  of  Medicine, 
W.  B.  Saunders  &  Co.,  Philadelphia,  1904,  p.  583. 

4  Ztschr.J.  Hyg.,  1894,  17,  p.  59.  '  New  York  Med.  Jour.,  1894,  60,  p.  i. 

s  Wien.  klin.  Rundschau,  1905,  19,  p.  253.  '  Compt.  rend.  Soc.  de  Biol.,  1904,  66,  p.  60. 

« Jour.  Exp.  Med.,  IQ05,  7,  p.  78. 

^Ztschr.f.  Hyg.  u.  Infektionskr.,  1891,  11,  p.  441. 

"  Op.  cit.  "  Ztschr.J.  Hyg.  u.  Infektionskr.,  1894,  18,  p.  343. 

"  Ztschr.  f.  klin.  Med.,  1897,  33,  p.  476. 


■^c,t  ■  REMOTE  STORAGE 

Secondary  Infection  in  Pulmonary  Tuberculosis  239 

The  opsonic  index  has  been  employed  by  Wirths^  to  determine  the  existence  of  a 
mixed  infection  in  tuberculosis  and  also  the  identity  of  the  particular  secondary  invader. 
In  a  series  of  clinical  cases  Wirths  found  the  index  constantly  normal,  i.e.,  between 
0.8  and  1 . 2,  in  all  cases  to  the  Diplococcus  capsulatus,  Micrococcus  tetragenus,  Micro- 
coccus catarrhalis,  meningococcus,  pneumobacillus,  pseudodiphtheria  bacillus,  colon 
-  Ci  bacillus,  B.  subtilis,  but  abnormal- to  the  influenza  bacillus  in  two  cases  of  17  (12  per 

>  ,  cent),  to  the  pneumococcus  in  18  cases  of  24  (75  per  cent),  to  the  streptococcus  in  six 
'-^  cases  of  19  (30  per  cent).    He  found  the  index  to  the  four  last  organisms  normal  in 

O  five  cases  of  25  (20  per  cent).    The  actual  value  of  the  opsonic  index  is  yet  to  be  deter- 

g  mined  by  a  more  extensive  application;  at  all  events,  the  results  are  not  at  present 

0  uniform  in  the  hands  of  all  workers.^ 
-S 

i*»  Leukocytosis  in  pulmonary  tuberculosis  has  been  employed  as  a  criterion  indica- 

tive of  a  mixed  infection  (Simon) 3  inasmuch  as  the  tubercle  bacillus  alone,  except  in 
i(7  acute  miliary  tuberculosis,  does  not  produce  a  leukocytosis.    Pick,  Warthin,  v. 

—  Jaksch,  and  Galbraith  found  the  number  of  leukocytes  in  uncomplicated  tuberculosis 
t         normal  or  low.    Strauer,  Grawitz,  Halbron,  and  Appelbaum  found  the  leukocytes 

normal  in  incipient  cases.    Ullon  and  Craig^  also  made  leukocyte  counts  on  a  con- 
c:::^'^'^  -  siderable  number  of  cases  and  found  an  average  of  10,285      cases  of  the  first  stage; 

12,772  in  the  second  stage;  and  14,041  in  the  third  stage.    I  have  made  leukocyte 

—  counts  on  112  cases  and  found  an  average  of  11,963  in  16  incipient  cases,  14,783  in  84 
advanced  cases,  and  15,820  in  12  far-advanced  cases. 

A  certain  grade  of  leukocytosis  is  not,  of  course,  rare  in  chronic  pulmonary  tuber- 
culosis and  a  distinct  leukocytosis  is  perhaps  indicative  of  a  mixed  infection;  the 
limitation  of  the  method  in  the  study  of  secondary  invaders  in  tuberculosis  is,  however, 
that  a  secondary  invader  may  be  present  without  producing  an  evident  leukocytosis, 
and  furthermore,  that  the  leukocytosis  when  occurring  gives  no  information  concern- 
ing the  character  or  location  of  the  secondary  invading  organism. 

Finally  there  remains  to  be  considered  the  blood-culture  method 
of  investigation.  It  has  long  been  recognized  that  the  finding  of 
secondary  invaders  in  the  blood  stream  in  pulmonary  tubercu- 
losis would  constitute  most  direct  evidence  as  to  the  importance 
of  the  role  played  by  such  organisms,  and  blood  cultures  have 
therefore  been  repeatedly  employed  in  attempts  to  show  the 
^  existence  of  such  a  bacteremia.  As  in  the  case  of  the  other  methods 
heretofore  cited,  however,  directly  contradictory  deductions  have 
been  made  by  those  employing  this  method.  But  in  this  instance 
I  believe  that  the  confusion  in  results  is  due  to  variations  in  the 
technic  used  rather  than  to  the  method  itself;  and  from  a  study 

V 

.  V  I  Beitrage  z.  klin.  d.  Tuberk.,  12,  p.  159. 

'  I  have  determined  the  opsonic  index  to  the  streptococcus,  pneumococcus,  and  staphylococcus  in  40 
cases  of  puhnonary  tuberculosis  and  have  found  the  index  between  o .  8  and  i .  2  in  all  cases  but  one,  and 
in  this  case  the  index  to  the  Staphylococcus  aureus  was  0.75.  As  in  Wirths'  work,  heterologous  strains 
were  used;  possibly  the  result  would  have  been  different  had  homologous  strains  been  employed. 

3  Clinical  Diagnosis,  Lea  Bros.  &  Co.,  1907,  Philadelphia  and  New  York. 

1  *  Trans.  Nat.  Ass.  Study  and  Prevention  Tuberculosis,  1905,  i,  p.  166. 


240 


RoswELL  T.  Pettit 


of  130  cases  of  pulmonary  tuberculosis  of  which  this  paper  is  a 
report,  I  am  convinced  that  blood  cultures  give  defmite,  positive 
proof  that  secondary  invading  organisms  are  present  in  the  blood 
stream  of  a  large  percentage  of  individuals  afflicted  with  pulmonary 
tuberculosis,  and  that  the  organisms  so  present  play  an  extensive 
role  in  the  production  of  the  symptoms.  Before  proceeding  to 
give  details  of  the  methods  and  results  of  my  own  work  however, 
it  may  be  well  to  analyze  the  previous  attempts  in  this  direction. 

By  way  of  introduction  it  may  be  stated  that  the  investigation 
by  means  of  blood  cultures  fall  into  two  groups,  namely,  those  of 
the  earlier  workers  and  those  of  relatively  recent  date.  The  early 
investigators  obtained  a  high  percentage  of  positive  results.  They 
secured  the  blood  by  pricking  the  ear  or  finger,  and  allowing  a 
few  drops  to  fall  through  the  air  into  culture  media.  The  chance 
for  air  and  skin  contamination  was  great,  and  the  number  of 
staphylococci  (chiefly  albus)  isolated,  indicates  that  the  large 
percentage  of  their  positive  findings  was  due  to  such  contamina- 
tions. On  the  other  hand,  the  later  investigators,  using  a  more 
trustworthy  technic,  drawing  the  blood  directly  from  a  vein  under 
attempted  aseptic  conditions,  have  shown  a  very  low  percentage 
of  positive  results — about  2.5  per  cent. 

Jakowski,^  puncturing  the  finger  and  allowing  the  .blood  to  drop  into  culture 
media,  secured  seven  positive  results  in  nine  observations.  Two  of  the  positive  cul- 
tures gave  streptococcus;  one,  streptococcus  and  staphylococcus  together;  and  four, 
staphylococcus. 

Hewelke^  found  organisms  in  14  out  of  21  cases.  Ten  were  staphylococcus;  one 
case  showed  a  diplococcus  and  one  case  a  non-pathogenic  organism,  either  a  coccus  or 
a  short  bacillus.  In  another  series,  using  venous  puncture,  he  obtained  three  positive 
results  out  of  13.  These  were  all  non-liquefying  white  cocci. 

Petruschky3  drew  a  definite  amount  of  blood,  and  injected  mice  and  inoculated 
culture  media.    He  found  streptococci  in  one  case  out  of  eight. 

Sittman,4  drawing  one  c.c.  of  blood  from  the  vein  at  the  elbow  in  four  cases, 
obtained  Staphylococcus  aureus  in  three  cases  and  Staphylococcus  albus  in  one. 

Schabad,s  using  the  same  method  as  Sittman,  recovered  Staphylococcus  albus  in 
one  case  out  of  three. 

Kraus,^  in  14  observations,  obtained  the  Staphylococcus  albus  in  one  case. 

Hirschlaff7  found  a  staphylococcus  in  four  of  35  cases. 

Von  Michaelis  and  Meyer^  found  bacteria  in  blood  cultures  from  eight  cases  in 

I  Centralbl.f.  Bakt.,  1893,  14,  p.  762.  s  Ztschr.f.  klin.  Med.,  1897,  33,  p.  476. 

» Ibid.,  1896,  19,  p.  563.  «  Ztschr.f.  Eeilkunde,  17,  p.  117. 

3  Deut.  med.  Wchnschr.,  1895,  19,  p.  317.  '  Deut.  med.  Wchnschr.,  1897,  13,  p.  766. 

•f  Deut.  Arck.f.  klin.  Med.,  1894,  53,  p.  323.  «  CkaritSannalen,  1897,  22,  p.  150. 


Secondary  Infection  in  Pulmonary  Tuberculosis  241 


10.  Five  of  the  organisms  were  staphylococcus,  one  was  a  diplobacillus,  one  a  gram- 
positive  diplococcus,  and  one  a  streptococcus.  The  blood  was  taken  shortly  before 
death — four,  three,  two,  nine,  and  14  days,  for  those  recorded. 

A.  Fraenkel,^  using  Sittman's  method,  obtained  negative  results  in  all  of  20  cases. 

Schroeder  and  Naegelsbach,^  putting  one  c.c.  of  blood  into  broth,  obtained  nega- 
tive results  in  all  of  eight  cases.  The  patients  were  far  advanced  and  all  died  within 
one  month  after  the  taking  of  the  blood. 

Straus^  found  the  blood  sterile  in  19  cases,  although  they  were  all  in  the  last  stages; 
most  of  them  with  marked  remittent  fevers. 

Lasker,-*  plating  two  c.c.  of  blood  in  agar,  obtained  but  one  positive  result  in  68 
cases.    This  case  showed  many  streptococci. 

Lemierres  found  the  blood  cultures  all  negative  from  eight  cases  in  the  last  stages. 

Teissier,^  investigating  53  cases,  obtained  nine  positive  results.  He  drew  one 
c.c.  of  blood  from  an  arm  vein,  and  divided  it  among  several  tubes  of  gelatin  and 
broth.  Of  the  nine  positive  results,  two  were  Staphylococcus  aureus,  three,  strepto- 
coccus, and  four  were  Staphylococcus  alhus. 

Jockmann,7  examining  40  cases,  drew  20  c.c.  of  blood  from  the  vein  at  the  elbow, 
distributed  this  among  six  or  seven  tubes  of  agar  at  45°  C;  after  shaking  thoroughly, 
the  contents  were  poured  into  Petri  dishes  and  incubated  at  37°  C.  All  the  results 
were  negative.  The  patients  showed  various  temperatures.  Some  were  of  a  remittent 
t5^e  and  cavities  were  present  in  almost  all  cases. 

Panichi^  found  pneumococci  in  four  cases  of  some  35  examined.  He  drew  scarcely 
one  c.c.  of  blood.  These  were  all  advanced  cases;  but  one  lived  for  seven  months  after 
the  blood  was  taken.  Panichi  concludes  that  bacteremia  may  occur  before  the  agonal 
period  and  be  intercurrent.  Pneumococci  were  found  in  one  case  that  did  not  give 
a  history  of  previous  pneumonia,  and  he  concludes  that  it  was  an  organism  coming 
from  a  cavity. 

Benohr,'  investigating  187  cases  of  tuberculosis,  making  241  examinations,  ob- 
tained four  positive  results.    He  drew  20  c.c.  of  blood  and  plated  it  in  glycerin  agar. 

F.  Reiche,^°  making  365  examinations  on  288  cases  of  high  fever  in  terminal  stages, 
took  15  to  20  c.c.  of  blood  and  obtained  1.65  per  cent  positive  results. 

The  workers  following  Sittman,  for  the  most  part,  drew  blood 
directly  from  a  vein  and  their  results  are  therefore  to  be  held  the 
more  reliable  in  that  the  possibilities  of  contamination  were  greatly 
reduced.  However,  many  of  the  positive  results  of  these  workers 
undoubtedly  included  contaminations,  namely  staphylococci  from 
the  skin.'  If,  however,  the  staphylococcus  findings  are  eliminated 
from  the  results  of  Tessier,  von  Michaelis  and  Meyer,  Hirschlaff, 

I  Berl.  klin.  Wchnschr. ,  iSgS,  35,  p.  345.  ^  Semaine  med.,  i8g4,  14,  p.  253. 

"  M'iinch.  med.  Wchnschr.,  1899,  46,  p.  1339.  ^  Deut.  Aertzte-Zeitung,  1901,  i,  p.  27. 

s  Bull,  et  mem.  Soc.  Med.  de  I'Hop.  de  Paris,  1903,  20,  p.  1437. 

^  Jour,  de  physiol.  gen.,  1901,  3,  p.  223.  ^  Deut.  Arch.  f.  klin.  Med.,  1905,  83,  p.  558. 

^  Berl.  klin.  Wchnschr.,  1908,  41,  p.  1840. 
9  Mitt.  a.  d.  hamb.  Staats-Krankenanst.,  1908,  13,  p.  323. 
^°  Med.  Klinik,  1909,  5,  p.  1962. 


242 


RoswELL  T.  Pettit 


Kraus,  Laskcr,  Schabad,  Sittman,  Panichi,  Jockmann,  Rciche, 
and  Bcnohr  and  others,  I  believe  their  positive  results  are  reliable; 
for,  as  discussed  later,  streptococci  and  pneumococci  are  not  organ- 
isms furnished  by  skin  contamination.  Excluding  the  staphylo- 
cocci, however,  the  results  of  these  later  workers  show  a  very  low 
percentage  of  positive  cultures  and  it  has  been  concluded  that  if 
secondary  infection  is  of  importance  at  all,  its  influence  is  due  to 
soluble  toxins  escaping  from  a  localized  infection  in  the  lung,  and 
not  to  a  bacteremia. 

My  own  experiments,  as  stated,  lead  me  to  quite  the  opposite 
conclusion,  namely,  that  the  invasion  of  the  blood  stream  by 
pyogenic  organisms  is  frequent  in  pulmonary  tuberculosis. 

In  carrying  on  my  work  I  have  given  emphasis  to  three  main 
points:  (i)  the  drawing  of  a  large  quantity  of  blood  under  the  most 
favorable  aseptic  conditions,  (2)  the  systematic  inoculation  of  the 
most  favorable  media  with  considerable  amounts  of  this  blood,  and 
(3)  the  rigid  exclusion  as  positive  cultural  results  of  all  organisms 
having  a  possible  origin  in  skin  or  air  contamination. 

To  cover  the  first  point  the  following  technic  was  employed  in  obtaining  the  blood 
for  cultural  purposes: 

From  5  to  20  c.c.  of  blood,  usually  the  latter  amount,  was  drawn  from  an  arm  vein 
by  means  of  a  glass  aspirating  bulb  of  about  25  c.c.  capacity.  A  cotton  plug  was 
placed  within  one  of  the  ends  and  a  piece  of  heavy  rubber  tubing  about  six  inches  long 
attached  to  this  end.  A  second,  shorter  piece  of  rubber  tubing  was  attached  to  the 
other  end.  An  antitoxin  needle  (No.  18  caliber)  was  inserted  into  the  distal  end  of  the 
shorter  piece  of  tubing  and  the  tubing  tightened  about  the  hilt  of  the  needle  by  bind- 
ing with  a  rubber  band.  The  needle  was  protected  by  slipping  a  test  tube  over  the 
end. 

Shortly  before  the  bleeding,  the  whole  aspirator,  including  the  tubings  and  needle 
with  a  test  tube  over  it,  was  wrapped  in  a  towel  and  sterilized  in  the  autoclave  at 
120°  C.  for  at  least  15  minutes. 

In  drawing  the  blood  the  upper  arm  was  encircled  tightly  with  a  rubber  bandage, 
the  cubital  region  was  scrubbed  vigorously  with  alcohol,^  anesthetized  quickly  with 
ethyl  chloride,  and  the  venous  puncture  made.  When  the  blood  commenced  to  flow 
into  the  aspirator,  the  compression  of  the  upper  arm  was  relieved,  and  the  blood 
aspirated  into  the  bulb  by  suction  through  the  heavy  rubber  tube  attached  to  the 
cotton-plugged  end  of  the  aspirator. 

» Various  methods  of  skin  sterilization  were  tried,  but  none  was  found  that  was  more  eflScient  than 
the  scrubbing  with  alcohol.  In  a  number  of  cases  the  skin  of  the  cubital  region  was  scrubbed  thoroughly 
with  green  soap,  and  rinsed  with  five  per  cent  carbolic  acid  and  i/iooo  mercury  bichloride.  In  another  group 
of  cases  the  cubital  region  of  the  patient's  arm  was  scrubbed  with  green  soap  and  painted  with  tincture  of 
iodin. 

The  percentage  of  cultures  showing  Staphylococcus  albus  after  these  methods  of  skin  preparation  was 
as  great  as  in  the  cases  in  which  simple  cleansing  of  the  skin  with  alcohol  was  used. 


Secondary  Infection  in  Pulmonary  Tuberculosis  243 


As  soon  as  the  required  amount  of  blood  had  been  withdrawn,  the  needle  was 
removed  from  the  vein,  a  wire  sterilized  in  the  flame  was  inserted  to  occlude  the  lumen 
of  the  needle,  and  the  whole  needle  then  heated  to  redness.  This,  with  the  resulting 
coagulation  of  the  blood,  effected  a  sealing  of  the  needle. 

In  making  the  transfer  from  the  aspirator  to  the  culture  media,  the  short  rubber 
connection  and  the  needle  were  detached  and  the  end  of  the  aspirator  heated  thor- 
oughly in  the  flame.  The  corks  of  the  culture  tubes  and  flasks  were  flamed,  the  corks 
removed  by  an  assistant,  the  necks  of  the  tubes  and  flasks  heated  thoroughly  in  the 
the  flame  and  the  desired  amount  of  blood  was  then  transferred  quickly  from  the 
aspirator  to  culture  flask.  The  end  of  the  aspirator  was  flamed  again  before  more 
blood  was  transferred  to  a  second  culture  flask.  In  spite  of  a  rigorous  enforcement 
of  this  technic  as  a  precaution  against  contamination  in  drawing  the  blood  and  in  trans- 
ferring it  to  the  culture  media,  contamination  by  staphylococci  occurred  in  lo  per  cent 
of  the  cases.  The  staphylococcus  undoubtedly  represented  a  skin  contamination  and 
in  a  control  series  of  2 1  blood  cultures  made  on  normal  individuals,  a  similar  contami- 
nation occurred  in  two  instances. 

In  the  attempt  to  grow  organisms  from  the  blood  obtained  in  the  manner  above 
given,  the  following  cultural  methods  were  employed.  Five  c.c.  of  agar  was  sterilized 
in  eight-ounce  flat  flasks,  and  immediately  before  using,  the  agar  was  melted  and  cooled 
to  40°  C.  From  one  to  two  c.c.  of  blood  was  introduced  into  each  of  one,  two  or  three 
of  these  flasks  containing  melted  agar,  and  after  the  blood  and  agar  were  thoroughly 
mixed  by  gently  agitating,  the  flasks  were  laid  on  the  side  and  the  agar  allowed  to 
harden,  giving  a  large  layer  of  blood  agar,  about  |  in.  in  depth.  The  flasks  Were  next 
put  in  the  incubator  at  37°  C. 

In  a  majority  of  the  cases  cultures  were  also  made  in  broth, ^  usually  five  c.c.  of 
blood  being  put  into  50  c.c.  of  broth.  No  particular  attention  was  paid  to  an  exact 
dilution  other  than  to  avoid  a  concentration  greater  than  one  to  10.  As  a  usual  routine 
two  or  three  such  inoculations  of  broth  were  made.  In  a  few  cases  flasks  of  litmus  milk 
were  used,  but  the  broth  was  found  to  be  much  more  satisfactory. 

The  residuum  of  the  blood  not  employed  in  the  above  inoculations  was  incubated 
in  the  sealed  aspirator  or  in  a  sterile  test  tube. 

After  24  hours  at  37°  C,  the  blood- agar  flasks  were  examined  with  a  low-power 
lens  with  especial  reference  to  the  presence  or  absence  of  deep  colonies  showing  hemo- 
lytic zones.  In  the  case  of  a  positive  finding,  typical  colonies  were  transferred  to  blood- 
agar  slants.  The  broth  was  examined  after  48  hours.  Microscopic  examination  was 
made  of  smears  stained  with  simple  gentian  violet  and  by  Gram's  method.  Blood- 
agar  plates  were  inoculated  with  one  c.c.  of  the  48-hour  broth  regardless  of  whether 
the  microscopic  findings  were  positive  or  negative.  In  a  considerable  number  of 
instances,  milk  tubes  also  were  inoculated  from  the  broth.  The  full  blood,  incubated 
for  24  hours  in  the  aspirator,  was  examined  microscopically  for  organisms,  and  whether 
the  finding  was  positive  or  negative,  transfers  were  made  at  once  to  blood-agar  slants. 
After  incubation  of  the  residuum  of  full  blood  for  an  additional  24  hours  (total  48) 
this  was  plated  in  blood  agar. 

The  blood-agar  transfers  obtained  as  above  indicated  from  the  original  blood 
agar  and  broth  and  from  the  incubated  full  blood,  were,  in  turn,  incubated  at  37°  C. 
for  24  hours.  The  resulting  growths  were,  in  all  instances,  streptococci,  pneumococci, 
or  staphylococci. 

.  '  Mallory  and  Wright  ,Technic.,  3d  ed.,  Saunders  &  Co.,  1904,  pp.  71,  73,  74. 


244 


RoswELL  T.  Pettit 


1.  Cultures  showing  a  clear,  dewlike  growth,  confined  to  the  needle  track;  or 
scattered,  clear,  fine,  pin-point  colonics  were  examined  microscopically  for  a  character- 
istic arrangement  of  the  organisms  in  chains  or  in  pairs.  Transfers  of  individual 
colonics  were  made  to  plain-agar,  potato,  gelatin,  milk,  broth,  dextrose-agar,  and 
serum-inulin-agar,  or  serum-inulin-water  and  blood-agar  and  the  cultural  study  of  the 
fully  isolated  organism  was  continued  in  each  instance  until  its  identity  was  established. 
Daily  descriptions  of  the  growths  were  recorded  for  six  consecutive  days. 

2.  The  24-hour  blood-agar  cultures,  which  in  contrast  to  those  described  above, 
presented  an  abundant  surface  growth,  were  examined  microscopically  for  staphylo- 
cocci, and  were  transferred  at  once  to  the  usual  series  of  culture  media.  An  organism 
forming  a  white  or  yellow  growth  on  plain  agar,  distinct  growth  on  potato,  liquefaction 
of  gelatin,  a  considerable  cloudiness  in  broth,  or  a  white  or  yellow  surface-growth  on 
dextrose  agar,  was  in  all  instances  assumed  to  be  a  staphylococcus,  was  identified  as 
such  and  was  discarded  as  presumably  representing  a  skin  contamination. 

As  above  stated  tJie  only  organisms  obtained  in  the  original 
cultures  of  the  entire  series  of  examinations  were  staphylococci, 
streptococci,  and  pneumococci;  and  inasmuch  as  the  staphylococci 
were  eliminated,  the  results  recorded  as  representing  actually 
positive  blood  cultures  have  to  do  only  with  streptococci  and 
pneumococci.  On  this  basis  alone,  however,  positive  results  were 
obtained  in  46  per  cent  of  the  cases  examined  (60  in  130).  The 
streptococcus  was  found  in  36  cases  and  the  pneumococcus  in  24 
cases. 

It  is  not  possible  within  the  scope  of  this  paper  to  give  in  detail 
the  bacteriological  results  for  the  entire  number  of  positive  cases. 
The  following  six  instances,  however,  serve  as  examples  of  the 
application  of  the  methods  outlined  above  and  the  results  obtained. 

"P." — Incipient  pulmonary  tuberculosis.  Temperature  normal.  Ambulatory. 
Disease  passive.  Hemorrhagic  history.  Family  history  indicates  marked  predisposi- 
tion to  tuberculosis.  Marked  infiltration  of  right  lung;  moderate  impairment  of 
upper  portion  of  left  lung. 

Cubital  region  of  arm  scrubbed  with  green  soap  and  painted  with  iodin.  Immedi- 
ately before  making  venous  puncture,  operator's  hands,  covered  with  gloves,  were 
dipped  in  95  per  cent  carbolic  acid  and  rinsed  in  mercury  bichloride,  i/iooo.  Ten  c.c. 
of  blood  was  drawn  from  median  basilic  vein  and  two  c.c.  transferred  to  each  of  four 
flasks  containing  five  c.c.  of  melted  agar  cooled  to  40°  C.  Agar  and  blood  were  thor- 
oughly mixed,  and  plates  made  by  laying  the  flasks  on  the  side.  When  agar  had 
hardened  the  flasks  were  put  in  the  incubator  at  37°  C.  After  18  hours,  numerous 
greenish  colonies  with  hemolytic  zones  were  seen  on  the  plates.^  Several  such  colonies 
were  transferred  to  blood-agar  slants.  Blood-agar  slants  after  24  hours  showed  dis- 
crete, greenish,  hemolytic  colonies,  shown  by  microscopic  examination  to  be  composed 

'After  72  hours,  plates  were  somewhat  overrun  with  surface  growth  of  white  colonies.  Smear  of 
this  latter  growth  showed  large  cocci  in  bunches.    Identified  as  Staphylococcus  albus. 


Secondary  Infection  in  Pulmonary  Tuberculosis  245 


of  gram-positive  cocci  arranged  in  long  chains.  Several  of  these  discrete  colonies 
were  transferred  from  the  agar  slants  to  a  series  of  media  with  the  following  results : 

Subcultures  after  24  Hours. 

Blood  agar:  Few  very  small,  dewlike,  clear  colonies.  No  increase  in  growth  after 
96  hours. 

Plain  agar:  Same  as  blood  agar,  only  much  less  extensive,  practically  invisible. 
No  increase  in  three  days,  slightly  increased  in  four  days. 
Potato:  No  growth  in  six  days. 

Gelatin:  No  growth  in  six  days  (room  temperature). 
Litmus  milk:  No  apparent  change. 
Broth:    No  apparent  growth. 

Dextrose  agar:  No  surface  growth;  questionable  growth  along  stab. 
Serum-inulin-agar:  No  change.  '  ' 

Diagnosis:  Streptococcus.^ 

"D." — Advanced  pulmonary  tuberculosis.  Condition  passive.  Ambulatory. 
Hemorrhagic  history.    Moderate  infiltration  of  both  lungs. 

Cubital  region  of  arm  scrubbed  with  alcohol  and  20  c.c.  of  blood  drawn  from 
median  basilic  vein.  Transferred  two  c.c.  immediately  to  an  agar  flask  containing 
five  c.c.  melted  agar  cooled  to  40°  C.  and  transferred  five  c.c.  to  each  of  three  iiasks 
containing  50  c.c.  of  broth.  The  remaining  blood  was  sealed  in  the  aspirator  and 
incubated  without  diluting. 

Subcultures  after  24  Hours. 

Blood  agar:  Showed  many  greenish  colonies  with  hemolytic  zones.  Several 
colonies  were  transferred  to  blood-agar  slants.  Smears  from  18-hour  blood-agar 
slants  showed  diplococci  in  short  chains  and  cocci  in  bunches.  Growth  on  various 
media  showed  streptococci  with  Staphylococcus-alhus  contamination.  A  colony  from 
the  original  blood-agar  decolorized  milk  in  24  hours,  and  the  smear  showed  many  cap- 
sulated  diplococci;  some  in  short  chains.    Pure  culture. 

Broth:  After  72  hours  transfers  were  made  to  blood-agar  slants.  These  subcul- 
tures, after  24  hours,  showed  fine,  compact,  opaque  growths.  Smear  showed  diplococci 
in  short  chains  and  groups.  The  cultural  characteristics,  staining  reactions,  and  mor- 
phological arrangement  of  the  organism  isolated  from  flask  No.  2  identified  it  as  a 
streptococcus. 

Full  blood:  Microscopic  examination  after  48  hours  of  the  three  c.c.  of  undiluted 
blood  incubated  in  the  sealed  aspirator  showed  diplococci  in  short  chains.  Transfers 
were  made  to  blood-agar  slants,  which  after  24  hours  showed  slight,  compact,  greyish- 
looking  growth.    Smears  from  the  same  showed  gram-positive  diplococci  in  long  chains, 

'  The  differentiation  of  the  streptococci  from  the  pneumococci — in  so  far  as  that  is  possible — was 
based  upon  the  following  criteria:  (i)  Appearance  of  colonies  on  blood-agar  slants;  (2)  Appearance  of 
colonies  on  blood-agar  plates,  green  colonies  with  imperfect  hemolysis  (fuzzy  border)  were  considered 
pneumococci,  while  clear  or  opaque  colonies  showing  zones  of  sharply  demarcated  hemolysis  were  consid- 
ered streptococci  if  showing  other  suggestive  characteristics;  (3)  Chain  formation  on  blood  agar  and  in 
broth;  (4)  Reaction  on  serum-inulin-agar  (Ruediger)  or  in  serum -inulin-water  (Hiss).  Growth  in  gelatin 
capsule  formation,  growth  on  plain  agar,  and  morphology,  were  taken  into  account  in  making  a  differentia- 
tion, although  they  were  not  considered  of  distinct  diagnostic  value.  It  need  hardly  be  added  that  apply- 
ing all  possible  criteria,  the  validity  of  an  absolute  decision,  as  to  which  one  of  these  two  groups  a  given 
organism  belonged  to,  was  questionable. 


246 


RoswELL  T.  Pettit 


which  were  plated  in  blood  agar,  with  resulting  colonies  showing  distinct  clear  zones 
of  hemolysis.    Transfers  were  made  to  a  scries  of  media  with  the  following  results: 

Blood  agar:  24  hours — fine,  dewlike,  compact  growth  along  needle  track;  48 
hours — growth  slightly  increased. 

Potato:  No  growth. 

Litmus  milk:  24  hours — slightly  acid(?);  72  hours — -acidified  and  coagulated. 

Gelatin:  No  growth  in  three  days. 

Broth:  No  growth.    Smears  after  three  days  negative. 

Dextrose  agar:  No  surface  growth.    Growth  along  stab(?). 

Serum-inidin-water:  No  acid  production. 

Diagnosis:  Streptococcus. 

"C." — Advanced  pulmonary  tuberculosis.  Disease  active.  Ambulatory. 
Marked  infiltration  of  right  lung. 

Twenty  c.c.  blood  was  drawn  and  two  c.c.  was  transferred  to  each  of  two  flasks 
containing  five  c.c  melted  a^ar  cooled  to  40°  C,  five  c.c.  were  put  in  each  of  two  flasks 
containing  50  c.c.  of  plain  broth,  and  remainder  of  the  blood  was  put  in  a  sterile 
test  tube. 

Blood  agar:  Both  were  sterile  after  48  hours. 

Broth:  Microscopic  examination  of  flask  No,  i  showed  gram-positive  diplococci 
in  short  chains.  Transfers  were  made  to  other  culture  media  after  48  hours  with 
results  as  follows: 

Blood  agar:  Very  scant,  scarcely  visible  growth  of  fine,  dewlike  colonies  after 
24  hours;  slightly  increased  after  72  hours.  Smear  showed  gram-positive  diplococci. 
Pure  culture. 

Plain  agar:  No  growth. 

Potato:  No  growth. 

Gelatin:  No  growth. 

Milk:  24  hours — acid;  smears  showed  gram-positive  diplococci.    Pure  culture. 

Broth:  Clear,  but  with  pellicle.  Smear  showed  moderately  long  chains  of  gram- 
positive  cocci  (12-24  cocci  in  a  chain).  Bacillus  seen.  Second  tube  was  inoculated; 
slightly  cloudy  in  three  days.  Gram-positive  diplococci  in  chains  were  seen.  Pure 
culture. 

Dextrose  agar:  No  growth. 

Serum-inulin-water  (Hiss):  Acid  in  four  days. 

Diagnosis:  Pneumococcus. 

"G. " — ^Far-advanced  pulmonary  tuberculosis.  Condition  very  active.  Large 
cavity.  Several  bad  hemorrhages.  Bed-ridden,  Marked  infiltration  of  both  lungs, 
more  pronounced  in  left, 

25  c,c,  of  blood  was  drawn  with  usual  technic  and  three  c,c.  of  blood  was  trans- 
ferred at  the  bedside  to  each  of  four  flasks  containing  five  c.c.  of  melted  agar  cooled 
to  40°  C.  Five  c.c.  of  blood  was  transferred  to  each  of  two  flasks  of  50  c.c.  broth.  The 
remaining  blood  was  sealed  in  aspirator  and  incubated  undiluted. 

Blood  agar:  After  24  hours  the  flasks  showed  many  small,  greenish  colonies  im- 
bedded in  the  blood  agar  and  also  a  surface  contamination.  Transfers  were  made 
from  several  of  the  deep  colonies  to  blood-agar  slants  but  the  subcultures  showed 
contamination  with  staphylococci.  Discarded  for  pure  cultures  obtained  from  the 
full  blood  as  below. 

Broth:  After  four  days  the  broth  showed  typical  lanceolate  diplococci,  gram 
positive.    No  subcultures  were  made. 


Secondary  Infection  in  Pulmonary  Tuberculosis  247 


Full  blood:  Smears  showed  diplococci  in  long  chains  at  the  end  of  24  hours.  Sub- 
cultures were  made  on  a  series  of  media  with  the  following  results : 

Blood  agar:  Fine,  clear,  dewlike,  moist,  elevated  colonies;  growth  confined  to 
needle  track.  Growth  increased  after  48  hours.  Smear  showed  gram-positive  diplo- 
cocci in  long  chains. 

Plain  agar:  24  hours — very  scant,  almost  invisible  growth;  48  hours — ^growth 
somewhat  increased;  six  days— no  further  change.  Smear,  after  24  hours,  showed 
long  chains  of  diplococci. 

Potato:  No  growth. 

Gelatin:  No  growth. 

Litmus  milk:  48  hours — acid.    Not  coagulated  in  six  days. 
Broth:  48  hours — visible  growth.    Slight  cloudiness  with  granular  sediment  in 
six  days. 

Dextrose  agar:  Scant  surface  growth(?);  scant  growth  along  stab.    No  gas. 
Serum-inulin-agar:  Acid  production  in  three  days. 

Diagnosis:  Either  pneumococcus  or  streptococcus — doubtful  as  to  which. 

"K. " — Far-advanced  pulmonary  tuberculosis.  Very  active.  Bed-ridden. 
Marked  infiltration  of  right  lung.  Cavity. 

Five  c.c.  blood  was  drawn  and  about  two  c.c.  of  blood  run  into  a  flask  containing 
five  c.c.  of  melted  agar  cooled  to  40°  C.  After  the  blood  was  mixed  with  agar  it  was 
plated  in  a  thin  layer  by  laying  flask  on  its  side.  The  remainder  of  the  full  blood  was 
sealed  in  the  aspirator  and  incubated. 

Blood  agar:  Negative  after  48  hours. 

Full  blood:  A  transfer  was  made  from  the  full  blood  to  a  blood-agar  slant,  after 
24  hours.  Twenty-four  hour  blood-agar  slant  showed  scattered,  small,  greyish, 
opaque  colonies.   Smear  showed  cocci  in  chains.    Transferred  to  other  media. 

Subcultures. 

Blood  agar:  Scattered,  small,  greyish,  opaque,  elevated,  moist  colonies  after  24 
hours.    Very  scant  growth.    Not  increased  in  five  days. 

Plain  agar:  Very  scant  growth  of  clear,  dewlike  colonies.  Growth  slightly 
increased  in  72  hours. 

Potato:  No  growth  in  six  days. 

Gelatin:  No  growth  in  six  days. 

Litmus  milk:  Acid  in  24  hours,  fine  coagulum  in  four  days. 

Broth:  Fine,  granular  sediment;  fluid  clear.  Smear  after  three  days  showed 
gram-positive  cocci  in  long  chains. 

Dextrose  agar:  Scant,  clear,  surface  growth.    Slight  growth  along  stab(?). 
Litmus-inulin-agar:  No  acid. 
Diagnosis:  Streptococcus. 

Blood  culture  made  again  one  week  later  and  the  streptococci  were  again  recovered. 

"V. " — Moderately  advanced  pulmonary  tuberculosis.  Active.  Ambulatory. 
No  hemorrhage.    Marked  infiltration  of  right  lung.    No  cavities. 

About  10  c.c.  of  blood  was  drawn  and  three  c.c.  was  transferred  immediately  to 
each  of  three  flasks  containing  five  c.c.  of  melted  agar  cooled  to  40°  C.  After  mixing 
blood  thoroughly  with  agar,  plates  were  made  by  laying  flasks  on  the  side.  After  24 
hours  at  37°  C,  several  green  colonies  surrounded  by  clear  zones  appeared  in  two  of 
the  flasks,  the  third  flask  remaining  sterile.    Some  of  these  colonies  were  transferred 


248 


RoswELL  T.  Pettit 


to  blood-agar  slants,  and  from  these,  after  24  hours,  subcultures  were  made  on  various 
media  with  results  as  follows: 

Blood  agar:  24  hours.  Scattered,  flat,  green  colonies,  which  clung  tenaciously 
to  the  culture  medium.''  Colonies  had  a  truncated-cone  appearance.  A  smear 
showed  capsulated  diplococci.  Growth  increased  after  48  hours.  No  further  change 
in  six  days. 

Plain  agar:  Very  small,  clear,  scattered  colonies  in  24  hours.  No  change  in  six 
days. 

Potato:  No  growth. 
Gelatin:  No  growth. 

Litmus  milk:  Acid  production  at  24  hours.    Coagulation  m  three  days.  Smear 
showed  gram-positive  diplococci,  lanceolate  in  shape. 
Broth:  No  growth. 

Dextrose  agar:  Good  growth  along  needle  track.    No  surface  growth. 
Diagnosis:  Pneumococcus. 

The  details  of  the  above  six  cases  are  representative  of  the 
findings  in  all  of  the  60  cases  from  which  pneumococci  or  strepto- 
cocci were  isolated. 

Twenty-three  of  the  60  strains  isolated  were  tested  as  to  their 
pathogenicity  for  mice,  and  16  were  found  lethal. 

Fifteen  strains  of  the  60  isolated  were  employed  also  in  con- 
junction with  the  homologous  sera  to  determine  whether  or  not 
the  presence  of  the  organism  in  the  blood  stream  had  modified  the 
opsonizing  value  of  the  serum.  In  the  case  of  10  of  the  15  sera 
(66  per  cent)  the  opsonic  index  for  the  homologous  organism  was 
abnormal,  namely,  below  0.8  or  above  1.2. 


Number 

Organism 

Opsonic  Index 

I  

Streptococcus 

0.8s 

Pneumococcus 

1.3 

3  

Pneumococcus 

0.7 

4  

Streptococcus 

0.9s 

5  

Pneumococcus 

0.5 

6  

Pneumococcus 

0.7 

7  

Streptococcus 

0.8 

8  

Pneumococcus 

0.75 

9  

Pneumococcus 

o-S 

10  

Pneumococcus 

1.3 

II  

Streptococcus 

0.8 

12  

Streptococcus 

0.7s 

13  

Streptococcus 

0.7 

14  

Streptococcus 

0.8 

IS  

Streptococcus 

0.7 

As  mentioned  previously,  a  total  of  130  cases,  including  instances 
of  all  stages  of  pulmonary  tuberculosis,  from  passive  incipient 
involvement  to  far-advanced  active  processes  with  cavity  forma- 

'  In  several  cultures,  organisms  were  isolated  which  displayed  this  characteristic. 


Secondary  Infection  in  Pulmonary  Tuberculosis  249 

tion,  were  examined.  Streptococci  and  pneumococci  were  recovered 
from  the  blood  in  60.  The  relation  of  the  bacteriological  findings 
to  the  various  stages  of  the  disease  are  given  in  the  following 
summary : 


Classification 

Number  of 
Cases  Examined 

Number  of 
Positive  Blood 
Cultures 

Percentage  of 
Positive  Blood 
Cultures 

Incipient  

Far  advanced  

12 
99 
19 

2 
45 
13 

16 

45 
68 

130  • 

60 

46 

An  analysis  of  this  summary  shows  that  positive  blood  cultures 
were  obtained  in  a  relatively  small  number  of  cases  classed  as 
"incipient,"  whereas  the  percentage  was  almost  three  times  as 
great  among  the  "advanced"  cases.  From  the  "far-advanced" 
cases  the  percentage  of  positive  results  was  almost  twice  that 
among  the  "advanced"  cases,  and  four  times  that  of  the  "incipient" 
cases;  58  of  the  60  positive  cultures  were  obtained  from  "ad- 
vanced" and  "far-advanced"  cases. 

The  general  relation  of  the  bacteriological  findings  to  the  grade 
of  fever  displayed  by  the  host  is  expressed  in  the  following  state- 
ment : 


Grade  of  Fever 

Number  of  Cases 
Examined 

Number  of  Posi- 
tive Blood  Cultures 

Percentage  of  Posi- 
tive Blood  Cultures 

Afternoon  temperature  below  ioo°  F .  .  .  . 
Afternoon  temperature  above  ioo°  F.  .  .  . 

6S 
65 

22 
38 

34 
58 

From  this  it  is  seen  that  approximately  two-thirds  of  the  posi- 
tive cultures  were  obtained  from  individuals  showing  a  very 
distinct  afternoon  fever. 

Could  it  be  shown  that  the  streptococci  and  pneumococci 
obtained  in  the  above  results  have  a  possible  source  in  air  or  skin 
contamination,  as  is  actually  the  case  with  the  staphylococci  for 
instance,  the  above  findings  would  be  of  little  or  no  import  in  the 
discussion  of  secondary  invaders.  Hektoen^  has  rightly  pointed 
out,  however,  that  such  contaminations  with  organisms  other  than 
-the  staphylococci,  if  occurring  at  all,  are  of  such  extremely  rare 
occurrence  in  cultures  with  blood  obtained  by  venous  puncture  as 

^Jour.  Am.  M.  Ass.,  1903,  40,  p.  683. 


RoswELL  T.  Pettit 


to  be  a  negligible  factor.  Rarely,  indeed,  is  it  possible  to  obtain 
streptococci  by  direct  inoculations  from  the  skin,  even  in  the 
absence  of  surface  sterilization.  Thus  Weaver,^  attempting  to 
cultivate  this  organism  from  the  skin  in  a  group  of  i8  scarlet- 
fever  cases,  was  successful  in  but  one  case,  and  Dreyer,  in  a  similar 
group  of  30  cases,  failed  to  cultivate  the  streptococcus  in  a  single 
instance. 

To  control  this  point  under  fully  parallel  conditions,  however, 
blood  cultures  were  made  from  21  normal  individuals,  employing 
exactly  the  same  technic  as  that  used  in  the  case  of  the  130  tuber- 
culous patients,  even  to  the  amount  of  blood  withdrawn — 10  to 
20  c.c.  The  results  obtained  were  in  accord  with  the  above  state- 
ments, namely:  Neither  streptococci  nor  pneumococci  were  en- 
countered in  a  single  instance;  whereas  Staphylococcus  pyogenes 
albus  was  present  in  two  cases.^ 

In  view  of  these  facts,  the  conclusion  seems  warranted  that  the 
pneumococci  and  streptococci  isolated  by  the  blood-culture  method 
used  in  the  present  instance  had  their  origin  not  in  an  extraneous 
source,  but  actually  in  the  circulating  blood  stream. 

The  high  percentage  of  positive  results  in  the  series  of  cases  here 
reported  contrasts  sharply,  to  be  sure,  with  the  results  of  previous 
workers  who  have  employed  the  blood-culture  method  in  studying 
secondary  infections  in  pulmonary  tuberculosis.  The  explanation 
of  this  difference  I  do  not  seek  to  establish  other  than  to  point  out 
that  in  the  present  series  a  large  number  of  cases  was  examined, 
a  large  amount  of  blood  was  used,  and  finally  the  cultural  condi- 
tions most  favorable  to  the  growth  of  the  organisms  in  question 
were  rigorously  maintained. 

The  isolation  of  the  pneumococcus  or  the  streptococcus  from 
the  blood  stream  of  more  than  one-third  of  the  cases  examined 
leads  me  to  the  conclusion  that  not  only  are  true  secondary  invading 
organisms  of  frequent  occurrence  in  pulmonary  tuberculosis,  but 
further,  that  in  many  instances  these  organisms,  entering  the 
blood  stream,  constitute  a  complication  of  extensive  pathological 
significance. 

'  Cited  by  Hektoen. 

"  The  skin  of  the  forearm  of  six  normal  individuals  was  entered  with  sterile  needles  which  were  then 
plated  in  blood  agar.  In  two  instances,  there  was  a  growth  of  the  Staphylococcus  pyogenes  albus,  the  other 
four  plates  remaining  sterile. 


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